1. Technical Field
The disclosure relates to a semiconductor device and a method for manufacturing the same, in particular, to a self-aligned top gate type thin-film transistor and a method for manufacturing the same.
2. Related Art
In recent years, with the advancement of the semiconductor manufacturing technology, the manufacturing of an active device has become easier and faster. The active device has been widely used as, for example, a computer chip, a cell-phone chip, or an active-device display. Taking the active-device display as an example, the active device may be used as a switch for charging or discharging. In order to ensure the active device with high reliability and high display quality, the active device is required to have a high-passing current under an on-state and to have a low-leakage current under the off-state.
In addition, current metal oxide semiconductor thin-film transistors are commonly made by bottom gate type thin-film transistor. The main reason is that a processing apparatus for manufacturing the bottom gate type thin-film transistor is compatible to an apparatus for manufacturing a conventional amorphous silicon thin-film transistor. However, the bottom gate type metal oxide semiconductor thin-film transistor has a poor resistance to water and oxygen species. On the other hand, the conventional top gate type metal oxide semiconductor thin-film transistor has a good resistance to water and oxygen species but without a self-alignment process. Therefore, the conventional top gate type metal oxide semiconductor thin-film transistor has a large device parasitic capacitance, requires a large device layout area which does not help the development of a high-resolution panel, and has a poor frequency response with the reliability of the device to be enhanced.